I would opt for no caulking and about 1/8" space on the bottom. No bedding on the top. When revarnishing remove the top to revarnish the top edge.
To fasten the box to the boat I would epoxy or 5200 several bits of stainless angle with screws from the inside of the box through the angle into the box. This would keep wood off the deck, let the wood dry out thoroughly and make for easy removal for refinishing. I would do my utmost to avoid fasteners in a cored deck. I have a similar situation with a vent box on my boat. I left a gap of about 3/16 all the way around for drainage and drying. On wooden boats one of the prime places for rot to start is where horizontal and vertical parts meet. I also left an 1/8" gap between my cap rail and hull all around the boat so this joint can dry out. I do bed things that need to be waterproof. When I do I use 1/8" dia wire as spacers (one can also use those little soft plastic "feet" you get in the hardware store as compressible spacers) when I bed the piece. For bedding I use 5200 or Silicone. After the bedding cures I remove the spacers (they just stick in between the boat and the piece a tiny bit) and snug down the fasteners to compress the bedding. Norm S/V Bandersnatch Lying Julington Creek 30 07.695N 081 38.484W > [Original Message] > From: Sea Quell crew. <[EMAIL PROTECTED]> > To: <[email protected]> > Date: 7/27/2008 1:57:51 AM > Subject: [Liveaboard] Question - attaching dorade boxes. > > > OK, this is a fussy detailed question, thanks for indulging me. > > This spring I removed and meticulously varnished the Dorade boxes. > They are similar to this one, except that top horizontal surface is a > removable dark tinted plastic, perhaps perspex; > http://www.ahoycaptain.com/shop/media/marinershw/new_pa2.jpg > > While the Dorades were removed, I re-drilled all the screw-holes > oversize, and filled them with epoxy. This protects the deck core from > water seeping via the screw-holes. > > The Dorade boxes were screwed to the fiberglass deck, but without any > caulking along the sides. Is that the correct way to install them, > without any caulking? There are weep-holes on the sides, so any water > has an exit path. The PVC tube (riser) inside is several inches above > deck, to reduce the chance of water ingress, and we have never had a > water problem. > > I'm considering using some caulk to eliminate trapped dirt and moisture, > to prolong the life of the varnish. It will be difficult to do a tidy > job of this, because the Dorades are mounted over non-skid (not a flat > surface). > > If I'm caulking the bottom Dorade-deck joint, perhaps I should caulk the > top Dorade-perspex joint for the same reason? (extend the life of the > varnish). > > What do you think? Caulking or not? Bottom only or top as well? Sikaflex > (white), or some other caulking instead? > > Thanks for your input, > -Neal. > > > _______________________________________________ > Liveaboard mailing list > [email protected] > To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard > To subscribe send an email to [EMAIL PROTECTED] > > To unsubscribe send an email to [EMAIL PROTECTED] > The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ > > To search the archives http://www.mail-archive.com/[email protected] > > The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard To subscribe send an email to [EMAIL PROTECTED] To unsubscribe send an email to [EMAIL PROTECTED] The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
